A customer has old 3/4 hardwood down now and doesn't want to refinish it. They want new 3/4 installed on top. Can it be done or do you have to put down a layer of ply first. How about laying the planks the opposite direction of whats down? Thanks

If the old floor is securely attached, you can install over it. First, you will need to renail any loose areas and flatten the existing floor. Treat it as a subfloor/underlayment. You will need to lay the new floor at a right angle (90 deg.) to the existing floor. You may also run the new floor at a 45 deg. angle to the existing floor. Just do not run it parallel unless you overlay the old floor with 1/2" CDX plywood.

Gary is right, but I had to make a comment...


That ain't right?

Finishing is just a fraction of the cost of new wood and installation(I assume prefinished)

Do they just not want the fumes? Or do they have so many furnishings, that you'll have to move one as you work?

Sounds like they have more money, then sense??????

Thanks for the replys. I'm not sure why they don't want to refinish it. I haven't actually looked at the job yet. But since I don't refinish floors who am I to argue with them?

Could be lots of things besides what you mentioned. Want a different type of wood (species), different size (width), grade (clear instead of #1), old floor has many gaps, real dark stain and now want a natural, numerous water stains that won't sand out, etc. I've done it on a few occassions. Usually though, if people have wood now, they refinish it.

We always sand the finish off of the old floor before installing a new wood floor on top or moisture can get trapped under the finish on the old floor if it has a poly type finish. We always have to deal with moisture problems here.
Buddy

How would moisture get trapped between the two?

If the finish on the existing floor is a poly type finish it is almost like having a layer of 6-mil poly on top of what is now a subfloor. I have seen the old floor under the new floor buckle and have done repairs and found the old floor to be very high in moisture so removing the finish may help the floor breath a little better.
It may sound extreme but we do have extreme moisture problems down here so we take the extra step.
Buddy

Buddy, makes you wonder where all that moisture came from... doesn't it?


Didn't you wonder where? Did you find where?

Yep, It's the Gulf of Mexico. One of the most humid places in the country.
Buddy

You can say that again. New Orleans too! Humidity at 100%. By the time you walk a block outside, you are soaked!

If the humidity effected the sublayer, why didn't it effect the top finished layer with a gain of moisture content?

It tells me, that moisture is getting to the joists and subfloor and sublayer of flooring, from the bottom. Same as going over concrete in the same manner, by trying to double up.

If you pulled the sublayer of flooring and installed the wood on the high moisture content of the subfloor, it would have done the same thing. Cupped and buckled.

Floorguy, The 30lb felt under the new floor will reduce the moisture intrusion to the new floor to an acceptable level but not trap the moisture. The layer of poly on the old floor underneath can trap the moisture under the finish as it tries to wick up through the floor to replace the moisture removed by the A.C. Heart Pine will turn white under the finish and oak will turn black, we see it all the time.
And yes, moisture is getting to the joist and subfloor from the bottom, some homes for almost 200 years. Many of these old structures have no subfloor at all. Many have hollow walls with 3/4" pine t&g on the inside walls and ceiling and cypress on the outside walls.
We see floors 100 years old and in good shape buckle after sanding off the old boat paint or wax, and applying poly. Not all will do it but we do everything we can to prevent it.
The moisture could get through the paint or wax finish but not the poly(plastic).
I hope that makes sense.
Buddy

Ahhh, yes I see what your talking about.

30-lb felt over the old floor, and nothing done to prevent the floor joist and subfloor from gaining moisture.

It is clear now.

Some are trying some type of closed cell foam sprayed under the floor and on the joist. Sometimes this can cause more rot. The moisture finds its way under the foam in some places, now the air is cut off to the damp wood because of the foam and the wood rots. Poly on the ground helps on the homes close to the ground but many of these homes are 5' and higher off the ground and open all around with 95 to 100% humidity underneath with the poly or without. The poly helps very little on them. Someone could make a good living here if they could come up with a good method of sealing out moisture on these beach front and other waterfront homes without causing them to rot.
A dehumidifyer under the house with the entire area sealed with no ventilation is another way some are trying.
It's a battle,
Buddy